27.5 A 30ppm <80nJ ring-down-based readout circuit for resonant sensors

Resonant sensors are a promising candidates for energy-constrained applications. For instance, the resonance frequency shift of polymer-coated MEMS resonators has been used to realize electronic nose systems for personalized health and environmental sensing [1]. Oscillator-based readout circuits for such sensors have been successfully implemented [2,3], but are relatively power-hungry, difficult to design in the presence of parasitic capacitance, and only provide information about the resonance frequency, f_res, while the quality factor, Q, often includes additional valuable information.